Disconnect Switch: Learn the Purpose, Cost, and Lead Time to Procure

Disconnect switch
Disconnect switch

Purpose of disconnect switch

  • Disconnect switches establish isolation points to enable equipment maintenance. They are installed on both sides of the circuit breaker, high-side of the transformer, and on the line exit.
Location of disconnect switches inside a substation
Location of disconnect switches inside a substation
  • Switches cannot and should not be used to interrupt load current or fault current. A switch operation takes place after the circuit is de-energized.
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Arcing shown here occurs due to capacitive charging current, not load current.

Cost of disconnect switch

A switch can be designed in numerous ways – vertical break, center break, side break, double side break, pantograph, etc. View some of them here. The prices below reflect your typical vertical break configuration.

  • 365kV 3000A motor operated disconnect switch: ~$50,000
  • 138kV 2000A motor operated disconnect switch: ~$20,000

Lead time to procure disconnect switch

~22 weeks for a high voltage switch.

Information on cost and lead time is for your general knowledge only. Contact vendor with your equipment specifications for actual figures.


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Disconnect Switch: Learn the Purpose, Cost, and Lead Time to Procure 1

Substation Major Equipment

It’s only stupid-simple, let’s begin.

What’s the purpose of a conventional power transformer?
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Which combination of devices would you use to implement power line carrier?
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In a distribution substation, the available ground-fault current on the low side of the step-down transformer is excessive, over-dutying the switching equipment. What is your cost-effective solution to reducing the fault current?
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You are building an interconnect station, tying wind farm generation to the power grid. At the substation, the sources are tied through a tie-breaker. Which device would you install to make sure the sources are synchronized?
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An industrial facility is plagued with voltage flicker (due to harmonics) and poor power factor at the service entrance. Which device would you install to fix both issues?
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A transformer develops an internal fault. Which device would you install on the transformer high-side to interrupt fault current?
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For which event should a surge arrester operate? Check all that apply.
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The average score is 41%

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